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Water hardness Climbing

I am confused, the pool CH is reading at 475 and seems to be climbing, the CH on the water source to the auto-fill when tested on its own is 100. Whats going on here, could the water be picking up Calcium from the pool?

Re: Water hardness Climbing

When water evaporates, only the water evaporates. The calcium doesn't, it stays in the pool. Then the auto-fill kicks in and puts some water (with a bit more calcium) into the pool. So over time, the total amount of calcium will go up.

It is also possible that you're picking up some calcium from the plaster, especially if it's new (< 1 yr old), but the main culprit is the fill water.
--paulr